Hydrogen (H), from the greek root hydro- for water, and gen- for generator, is the most essential element in the universe, making up the majority of all matter. Together with oxygen, it creates water, which makes up over 70% of our body mass. It exists stably as a diatomic gas, H₂, in an inert environment or vacuum. However, in the presense of oxygen, hydrogen immediately forms water, hence its name.

It can be isolated from water if done with a proper gas capture electrolysis setup.

A 12 volt car battery works well for this application. Use distilled water with a bit of table salt added to make it conductive. The vials should be full of water to begin to ensure no atmosphere is present – Oxygen will be removed from the hydrogen tube automatically through the production of water, but nitrogen, which composes 78% of our atmosphere, will remain.

Hydrogen can also be generated readily by adding aluminum or zinc to hydrochloric acid. Be aware that either reaction generates considerable heat and gas; do not have a closed plastic bottle of hot acid explode on you when the reaction with aluminum foil begins a minute after combining… trust me!

Hydrogen is highly flammable, so exercise precaution in storing it.